The Toolkit libraries are standalone libraries which have their own releases,
bug trackers and in some cases active developer communities around them. The
toolkit acts as an umbrella project to deal with aspects which span multiple
of these libraries or have impacts on the dependent frameworks.

The set of libraries that is part of the Toolkit can change over time depending
on how these libraries evolve and are used. New libraries considered for
inclusion can be added to the set, and existing libraries no longer used can be
removed from the set.

So the set of Zope Toolkit libraries is not static; what is included
continuously evolves. The project maintains a list of which libraries are part
of the Toolkit.